A belt driving apparatus is installed in an engine of a vehicle, and the belt driving apparatus is installed on a front side of the engine of the vehicle to perform startup and driving of the engine, torque boosting of the engine, and power generation of a generator.
The belt driving apparatus may include a crank pulley provided in a crank shaft of an engine, an alternator pulley provided in a shaft of a generator (or an alternator), one or more auxiliary machine pulleys provided in shafts of one or more auxiliary machines (a water pump, a compressor, and the like), belts wound between any two of the crank pulley, the alternator pulley, and the auxiliary machine pulleys, and tensioner that provides the belts with tensions.
In a hybrid vehicle system, the engine may be started by a generator in addition to a starter, and torque boosting may be made by the generator during driving of the vehicle. A battery may be charged through generation of power during braking of the vehicle.
In this way, as the crank shaft and the generator are selectively driven as power sources for generating power, a tension side and a release side of the belt may be frequently changed, and accordingly, at least two tensioners provide tension to the belt.
However, according to the related art, since the at least two tensioners are installed, a layout of the front side of the engine is complex, and depending on the specification of the engine, it may be impossible to assemble or mount two tensioners on the engine.
Further, according to the related art, since the at least two tensioners provide the belt with a tension, the tension on the belt may become excessively high, lowering fuel efficiency.
In addition, since the at least two tensioners are required, the weight thereof may increase and the manufacturing costs may rise as well.